The invention discloses a fountain solution, which is characterized in that: the fountain solution comprises the following raw materials in percentage by weight: 1 to 15 percent of glycerin, 0.1 to 10 percent of ammonium citrate, 0.1 to 10 percent of malic acid, 0.1 to 5 percent of defoaming agent, 0.1 to 10 percent of wetting agent, 0.1 to 5 percent of bactericide, 1 to 15 percent of L-PCA-Na, 1to 15 percent of propylene glycol and 1 to 15 percent of sorbierite; and the preparation method comprises the following steps: adding the ammonium citrate, the malic acid, the wetting agent, the L-PCA-Na in a weight percentage ratio, then adding 50 to 80 percent of water, uniformly mixing the materials and the water; and adding the propylene glycol, the sorbierite, the glycerin, the defoaming agent and the bactericide into the obtained mixture and then uniformly stirring the mixture so as to obtain the fountain solution. The fountain solution has the advantages of environmental protection, strong fountain capability, wet non-verbal-visual part, sufficient PH-value buffering, difficult ink emulsification, large electric conductivity, large surface-tension buffering range and easy operating control.